A problem associated with conventional keyboards, Repetitive Stress Injury (also known as Repetitive Motion Injury or Carpal Tunnel Syndrome) ("RSI") has received considerable attention. A discussion of the problem is set forth in detail in U.S. Pat. No. 5,137,384 (Ergonomic-interface keyboard system) issued Aug. 11, 1992 to Spencer and Albert, which is incorporated herein by reference.
Attempts to address the RSI problem include a number of issued United States Patents, each of which are incorporated herein by reference.
U.S. Pat. No. 5,137,384 (Ergonomic-Interface Keyboard System), issued Aug. 11, 1992 to Spencer and Albert, discloses a keyboard which is split into two laterally spaced, vertically oriented halves, coupled with visual-reference mirrors that allow the user to visually reference the keyboard surface. PA1 U.S. Pat. No. 4,378,533 (Data Input System Using A Split Keyboard), issued Mar. 29, 1983 to McCall, discloses a divided keyboard set upon a common transverse platen which enable the user to space and orient horizontal keypads at a comfortable interval. PA1 U.S. Pat. No. 4,913,573 (Alpha-Numeric Keyboard), issued Apr. 3, 1990 to Retter, discloses a keyboard arranged into two separate horizontal keypads which feature portions wherein the keys are set on a vertical plane. PA1 U.S. Pat. No. 5,004,196 (Keyboard Accessor) issued Apr. 2, 1991 to Gross, discloses dual laterally adjustable horizontal hand-palm rests relative to a substantially conventional horizontal keyboard. PA1 U.S. Pat. No. 4,661,005 (Splitable-Keyboard For Word-processing Typing And Other Information-input Systems), issued Apr. 28, 1987 to Lahr, discloses a keyboard in which two keypads may be moved apart and pivotally adjusted toward 45 degrees of slope. PA1 U.S. Pat. No. 5,129,747 (Keyboard), issued Jul. 14, 1992 to Hutchinson, discloses a keyboard in which the rows of keys are arranged in a chevron shape. PA1 U.S. Pat. No. 4,515,086 (Adjustable Word Processor Work Station), issued May 7, 1985 to Kwiecinski and Yauger, discloses a work station for a word processing system, the keyboard of which may be adjusted to limited heights and limited angular adjustment. PA1 U.S. Pat. No. 5,073,050 (Ergonomic Keyboard Apparatus), issued Dec. 17, 1991 to Andrews, discloses another split keyboard which provides means for tilting the two halves. PA1 U.S. Pat. No. 5,017,030 (Ergonomically Designed Keyboard), issued May 21, 1991 to Crews, discloses a keyboard inclined at an angle substantially equal to the inclination of the forearm of the user. PA1 U.S. Pat. No. 4,658,124 (Keyboard Having Variable Inclination Of The Key Plant), issued Apr. 14, 1987 to Bertina, disclosed another keyboard which may be tilted. PA1 U.S. Pat. No. 4,402,624 (Device For Adjusting The Slope Of A Keyboard), issued Sep. 6, 1983 to Stahl, discloses a device for changing the angle of inclination of the working face of a keyboard. PA1 U.S. Pat. No. 4,483,634 (Keyboard Arrangement), issued Nov. 20, 1984 to Frey, discloses a keyboard subdivided into two keyfields which rise from the operator side of the keyboard and which enclose an angle open towards the operator but which are mounted on a substantially rectangular support. Frey notes that other arrays of keys are possible, including arc-like rows with the concave side of the arcs facing the user. While Frey states that this would result in a better adaptation to the different lengths of the fingers, he also notes that "a consistent realization of this principle . . . would result in different distances of the keys in the different rows" and provides no solution for this drawback. PA1 U.S. Pat. No. 3,945,482 (Orthogonal Input Keyboards), issued Mar. 23, 1976 to Einbinder, discloses an orthogonal ten-finger keyboard (a plurality of vertically oriented keys adjacent to horizontal home keys). While Einbinder also suggests differences in key top heights to compensate for differences in finger lengths, the height of keys operated by the little finger are tallest, followed by keys operated by the fourth finger, precisely the opposite arrangement of the present invention. PA1 U.S. Pat. No. 4,597,681 (Adjustable Keyboard), issued Jul. 1, 1986 to Hodges, discloses a divided keyboard in which each key is separately adjustable angularly, laterally and in height. The Hodges invention could, of course, be employed to create the variation in heights taught by the present invention, but Hodges does not disclose or motivate any deviation from the rectangular arrangement of keys. In fact, Hodges specifically calls for a keyboard "mounted upon a rigid, flat, rectangular support". PA1 U.S. Pat. No. 5,141,343 (Compressible/Expandable Keyboard With Adjustable Key Spacing), issued Aug. 25, 1992 to Roylance, discloses a keyboard with adjustable spacing between the keys for the purpose of allowing a full-size keyboard to be compressed for storage. PA1 U.S. Pat. No. 4,735,520 (Key Holding Structure Of Keyboard With Curved Operating Surface Of Keys), issued Apr. 5, 1988 to Suzuki and Takagi, discloses a keyboard having a downwardly curved keyboard surface which parallels a downwardly curved key holder plate. PA1 U.S. Pat. No. 4,528,428 (Key-Holding Structure Of Keyboard With Curved Operating Surface Of Keys), issued Jul. 9, 1985 to Gotoh and reissued Jul. 4, 1989 (RE 32,974), discloses a keyboard with a curved operating surface wherein the top faces of its keys define a downwardly convex profile in cross-section.
In addition, the following United States Patents provide keyboards designed for comfort of the user. Again, these are incorporated herein by reference.
Each of these disclosures provide for tilting the entire keyboard while maintaining the essentially planar and rectangular nature of the keyboard itself.
A number of the individual features of the present invention may be found, although not in the combination disclosed and claimed herein, in the following United States Patents, each of which is incorporated herein by reference.